From 5ce3e0ea8662bd655fd4761452a7e3b0e2e8b389 Mon Sep 17 00:00:00 2001 From: Xiu Jianfeng Date: Tue, 2 Jul 2024 12:57:28 +0000 Subject: [PATCH] mm/hugetlb_cgroup: introduce peak and rsvd.peak to v2 Introduce peak and rsvd.peak to v2 to show the historical maximum usage of resources, as in some scenarios it is necessary to configure the value of max/rsvd.max based on the peak usage of resources. Since HugeTLB doesn't support page reclaim, enforcing the limit at page fault time implies that, the application will get SIGBUS signal if it tries to fault in HugeTLB pages beyond its limit. Therefore the application needs to know exactly how many HugeTLB pages it uses before hand, and the sysadmin needs to make sure that there are enough available on the machine for all the users to avoid processes getting SIGBUS. When running some open-source software, it may not be possible to know the exact amount of hugetlb it consumes, so cannot correctly configure the max value. If there is a peak metric, we can run the open-source software first and then configure the max based on the peak value. In cgroup v1, the hugetlb controller provides the max_usage_in_bytes and rsvd.max_usage_in_bytes interface to display the historical maximum usage, so introduce peak and rsvd.peak to v2 to address this issue. Link: https://lkml.kernel.org/r/20240702125728.2743143-1-xiujianfeng@huawei.com Signed-off-by: Xiu Jianfeng Cc: Baolin Wang Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Miaohe Lin Cc: Sidhartha Kumar Cc: Tejun Heo Cc: Zefan Li Signed-off-by: Andrew Morton --- Documentation/admin-guide/cgroup-v2.rst | 8 ++++++++ mm/hugetlb_cgroup.c | 19 +++++++++++++++++++ 2 files changed, 27 insertions(+) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 02dc54fe1f5304..13736a94edfd72 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -2659,6 +2659,14 @@ HugeTLB Interface Files hugetlb pages of in this cgroup. Only active in use hugetlb pages are included. The per-node values are in bytes. + hugetlb..peak + Show historical maximum usage for "hugepagesize" hugetlb. It exists + for all the cgroup except root. + + hugetlb..rsvd.peak + Show historical maximum usage for "hugepagesize" hugetlb reservations. + It exists for all the cgroup except root. + Misc ---- diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c index e716c4671a1595..d8d0e665caed90 100644 --- a/mm/hugetlb_cgroup.c +++ b/mm/hugetlb_cgroup.c @@ -583,6 +583,13 @@ static int hugetlb_cgroup_read_u64_max(struct seq_file *seq, void *v) else seq_printf(seq, "%llu\n", val * PAGE_SIZE); break; + case RES_RSVD_MAX_USAGE: + counter = &h_cg->rsvd_hugepage[idx]; + fallthrough; + case RES_MAX_USAGE: + val = (u64)counter->watermark; + seq_printf(seq, "%llu\n", val * PAGE_SIZE); + break; default: BUG(); } @@ -739,6 +746,18 @@ static struct cftype hugetlb_dfl_tmpl[] = { .seq_show = hugetlb_cgroup_read_u64_max, .flags = CFTYPE_NOT_ON_ROOT, }, + { + .name = "peak", + .private = RES_MAX_USAGE, + .seq_show = hugetlb_cgroup_read_u64_max, + .flags = CFTYPE_NOT_ON_ROOT, + }, + { + .name = "rsvd.peak", + .private = RES_RSVD_MAX_USAGE, + .seq_show = hugetlb_cgroup_read_u64_max, + .flags = CFTYPE_NOT_ON_ROOT, + }, { .name = "events", .seq_show = hugetlb_events_show,